This study uses cytochemical tests, electron spectroscopic imaging and electron energy loss spectroscopy techniques to identify and localize the reserves inside the generative cell of Hermodactylus tuberosus pollen. Cytochemical probes applied to sections observed by light and transmission electron microscopy indicated that the generative cell contains large osmiophilic bodies probably made of phytic acid rich in P and Ca. The significance of the rich granulations in generative cells of Hermodactylus pollen is discussed in relation to floral biology and environmental conditions. In comparison, the vegetative cytoplasm contains (a) lipid droplets formed by unsaturated lipids and related to vacuoles, (b) lipid bodies with larger dimensions, irregular in shape and very rich in Ca, (c) bodies stained in polysaccharide tests as well as lipid probes tentatively identified as glycolipid granulations, and (d) small granules very rich in P and Ca interpreted as phytin granules.
Alterations in the genetic apparatus of mice bone marrow cells and testicles caused by Hymenolepis nana, Ascaris suum and Toxocara canis metabolites have been investigated by means of micronuclear test application. The activity of spermatogenesis has been investigated at experimental hymenolepidosis, migrating ascariasis and toxocarosis with the use of ³H-timidine. Helminths metabolites have been established to exert a mutagenie effect on somatic cells of bone marrow, spermatogonies and also on the generative cells (spermatides) of helminths in invaded mice. The concurrent increase in micronucleus number in erythrocytes, spermatogonies and in spermatides (to a lesser degree) of invaded mice has been revealed. The decrease in spermatogenesis activity has been established in experimental hymenolepidosis, migrating ascariasis and toxocarosis in invaded mice.
Oenothera hookeri L. pollen germination and pollen tube growth proceed in very similar ways in the pistil and in vitro. A characteristic feature of pollen grain germination is the emergence of one or more pollen tubes from 1, 2 or 3 colpi at the same time. The second specific event is the different way pollen tubes branch during their growth. The present study compares germination and pollen tube growth in fresh and frozen pollen grains. Pollen grain viability was estimated by fluorescein diacetate staining and tested by germination on medium. The localization of nuclear and plastid DNA was detected after DAPI staining. Sperm cell and vegetative nucleus positions were observed in only one of the pollen tube branches and pollen tubes germinating from the same pollen grain. The vegetative nucleus was weakly stained and its fluorescence was dim. The nuclei of sperm cells were very well seen and were found at different distances from the pollen tube tip. After a period of incubation the pollen tube containing sperm cells was always longer than other tubes or branches germinating from the same pollen grain. In some tubes the sperm cell nuclei seemed to change position from one branch to another. Sperm cells probably can move within the pollen tube growing in the ovary to the branch closest to the embryo sac.
In order to study microtubule organization during pollen germination and pollen tube growth in Olea europaea, we applied immunofluorescence microscopy using mouse monoclonal antibody against α-tubulin as primary antibody and FITC-conjugated goat antimouse IgG as secondary antibody. DAPI enabled observation of the vegetative nucleus entering the emerging pollen tube before the generative cell. The latter then overtakes the vegetative nucleus once both are inside the pollen tube. The generative cell remains ahead of the vegetative nucleus until it is finally divided into two gametes. This cell division occurs when the generative cell is close to the tip of the pollen tube. Possible connections between microtubules and nuclear migration in the pollen tube are discussed.
One recent advance in plant embryology is the experimental manipulation of various reproductive cells and their protoplasts under in vitro conditions. These experimental means may be helpful for understanding the developmental biology of sexual plant reproduction, on one hand, and developing novel methods in biotechnology, on the other. This article reviews a series of our works in this field. The article includes manipulation of pollen protoplasts, de-exined pollen, male gametoplasts and female gametoplasts. Each section starts with isolation of the cells/protoplasts and is followed by further manipulations such as culture, fusion, gene transfer, and also some cell biology studies based on and related to these manipulations.
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